Remove Postgres driver from play-heroku artifact
Remove Postgres driver from play-heroku artifact

jkutner/heroku-buildpack-play,lendup/heroku-buildpack-play,mlimotte/heroku-buildpack-play,luis1van/heroku-buildpack-play,Nitro/heroku-buildpack-custom,jamesward/heroku-buildpack-play,cloudControl/buildpack-play,toasttab/heroku-buildpack-play,gooichi/heroku-buildpack-play,Scalingo/play-buildpack,hpcloud/heroku-buildpack-play,tazmaniax/heroku-buildpack-play,jakeyr/heroku-buildpack-play,heroku/heroku-buildpack-play